Dripping inejction usually takes some long hours to finish, so it is impossible for the nurses to take care of patient at bedside all the time. In general cases, nurses just leave away after dripping injection is arranged to begin and would come back to veiw the condition only occasionally. That easily causes the patient to grow psychological fear and complaint and is unable to take a full rest, since he or she may fear the air may enter to the blood vessel to cause danger at end of the dripping injection when nurse fails to come to handle timely.
FIG. 1 shows a conventionally used dripping liquid barrel A for dripping injection procedure. Dripping liquid barrel A is provided with a penetrating needle B for stabbing stopper into a fluid bottle (not shown in the figure) to guide the fluid drippingly thereinto, and has a flexible outlet pipe C connected to its bottom floor for fluid delivery. However, it has the sole function in reducing pressure for outlet pipe C. Still, if the injection needle (not shown in the figure) fails to be removed before fluid depletion, there would be danger of the air entrance into human body way of the injection needle. FIG. 2 shows an improved dripping liquid barrel D. Dripping liquid barrel D has a float ball E therein which can be supported to depart from fluid outlet G fluid by volume F, so that float ball E may come down to block outlet G, when loosing support of fluid volume F, to prevent air entrance into outlet pipe H. But, as a matter of fact, the bottom of dripping liquid barrel D is plane form for which reason float ball E will not necessarily land on outlet G as wished, and even if float ball E lands and block G, this sort of sealing is merely for the time being. It no doctor or nurse comes to handle in time, there would still be danger of air entrance into human body.